1. Field of the Invention
The present invention relates to a method and apparatus for dynamically measuring the stiffness of a tire and wheel assembly.
2. Background Art
The stiffness of a wheel rim can effect the ride, steering, and handling of a vehicle. Wheel styling, durability and other parameters may impact the stiffness of a wheel. If the stiffness of a wheel changes, the suspension tuning in the design process may be impacted. Changes in wheel stiffness may require changes in base vehicle tuning which, in turn, may require component design changes.
There is a need for a method to assess wheel assembly stiffness when the tire is assembled to the wheel in a simulated road test environment. Current physical testing and finite element analysis (FEA) methods do not adequately capture the wheel deflections or the complex wheel to tire interface since the constraints imposed on the system are not necessarily representative of actual driving conditions.
There is a need for a method of assessing effect of wheel assembly stiffness on vehicle dynamics under actual dynamic conditions that simulate vehicle driving conditions for both lightly loaded and heavily loaded conditions. By understanding the effects of wheel assembly stiffness, program development teams may be able to better assess the effect of a wheel design change made during the development process and control the extent of wheel assembly stiffness changes made during the development process. This will help ensure the realization of vehicle tuning objectives relating to ride, steering and handling of a vehicle.
The above problems are addressed by the method and apparatus as summarized and described below.